I'm at a loss what to do next.

我对下一步做什么心里没谱。

《牛津词典》

I don't know what to do next.

我不知道接着该做什么了。

《柯林斯英汉双解大词典》

We rarely agree on what to do.

我们很少在要做的事情上看法一致。

《牛津词典》

Play it by ear also means to decide what to do at the last minute instead of making detailed plans.

VOA: special.2009.09.13

But it's giving me ideas of what to do in the class when tied into what I'm teaching as well.

不过这启发了我以后如何讲课,如何把它跟我教的课程相结合。

麻省理工公开课 - 媒体、教育、市场课程节选

when other people that might not have been involved with the sport wouldn't really know what to do.

而或许没参与过这项运动的人连做什么都不知道。

体育相片的魅力 - SpeakingMax英语口语达人

Just as Baier was mulling over what to do, Nasdaq began its swan dive.

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"It's so complicated that no one really knows what to do, " says Prof Jankovic.

BBC: How Croatia and Serbia buried the hatchet

Moreover, League says, there's the issue of what to do if the box crashes.

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